If you are a Firefox user, you might have been depending on third party softwares to view the PDF documents. When you click a PDF link on your Firefox browser, it would download the PDF file into your PC for viewing it.

Avid PDF users might consider switching to google chrome as it supports direct PDF viewing functionality inside the browser.

Firefox 15 now comes with the ability to view PDF files without depending on any third party addons. Though firefox comes with PDF viewer built in, it is not enabled by default.

Enabling PDF Reader in Firefox 15

  • Make sure you are using Firefox 15, Press Ctrl + T to open up a new Tab in firefox.
  • Now in the address bar, type about:config and press Enter and you’ll be shown a warning before proceeding further. Click on ‘ I’ll be careful, I promise! ’.
  • Type browser.preferences.inContent in the search bar to see the corresponding entry being displayed.
  • Doubled Click on the entry to change its value from False to True.
  • Similarly you’ll have to type pdfjs.disabled in search and change its value from True To False.

    firefox 15 pdf viewer

    Setting pdf.js disabled to True

  • Now from the Menu bar click on Tools > Options > Applications and type PDF in the search box beneath.
  • Firefox would show you the default application set to open up PFD files. Under Action, choose Preview in Firefox and you’re set.

    viewing PDF files inside firefox 15

    Setting Firefox 15 default PDF Viewer

Firefox would now be able to show you PDF files within the browser itself without requiring any of the additional addons or plugins.


Amal Roy is the Founder-Editor of Computing Unleashed. A Technology Enthusiast, Windows Adept and a Proud Geek! | Connect with him on Google+